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Atoms and the Physical World

This blog is based on Walter Terrence Stace article called Sir Arthur Eddington and The Physical World, in the journal Philosophy, Vol. 9, No. 33 (Jan., 1934), pp. 39-50. The article follows that of Refutation of Realism (which I did a blog on).

He starts out by pointing out the two distinct worlds of the familiar world and the physical world. The first, familiar world contains sticks, stones, stars, colors, sounds, and smells. The second, physical world, contains electrons, protons, and has no colors, smells, or taste.

The familiar world is suppose to be composed of “sense-data”, and that they only exist in the mind, or are subjective. The physical world is to be composed of something that interacts with us, and gives rise to the “sense-data” that we experience. We reach to the physical world by inference from the familiar world that we experience, to the world outside of it by inference. This means we never come into direct contact with the physical world, like we never see it, touch it, smell it, or taste it. Thus, we only infer from the sense-data, which are ‘in the mind’, to the physical world of electrons and protons. But the electrons and protons aren’t hypothetical entities or fictions (as Eddington might think).

To clear up some of these things, this will not deal with common-sense division of universe of mind and universe of matter. This is to be considered false, because there is a third option. There is the third realm of neither physical nor mental, but what will be called a “neutral” realm. Part of this neutral realm is our sensory qualities, and are neither physical or mental. This is one way to get ride of this division of mind and matter (known as Neutral Monism).

We come to recognize that “Sense-data are the first and the most direct things in our experience; all else is remote inference.” It does not matter if they sense-data are mental or neutral, “in” minds or “outside” of them. What matters is that we don’t attribute these “sense-data” to atoms, because we’re told that don’t have color or anything like that, which are sensory qualities. For we’ll be stuck in a contradictions: “Electrons have color but they don’t have color.”

Let’s take a statement like, “There exists a physical world of protons and electrons which do not possess the sensory qualities. And this world is not in any way hypothetical or fictitious.” And we’ll come to think of it like saying something like the cat is real, the moon is real, the table is real. Come to understand it simply as “existent”.

Now let’s take a look at what happens if we take protons and etc are merely fictitious. We can soften the language and just call them “mental constructions”. This view doesn’t say anything about the validity of science, or the invalidity, nor does it derogates the dignity of it’s claim to teach us “truth”. There existence is more of an ontological question, one of metaphysics. As mathematician and scientist Henri Poincare once said, “It matters little whether ether really exists; that is the affair of metaphysicians. The essential thing for us is that everything happens as if it existed, and that this hypothesis is convenient for the explanation of phenomena.” And physicist Edward Andrade once said, “Whether the man of science regards his atoms as having an ultimate reality or not does not affect the validity of theory; the theory is just as useful in introducing order and promoting discovery if they are merely polite fictions as if they are desperate realities.”

Because we only experience the sense-data, this rules out the suggestion that we can know that atoms exist by perceiving them. They are outside of the sense-data, as the scientist would admit. But we can admit that we perform an experiment and notice that we see a “wavy trail”, and we call that the electron. But we haven’t seen the electron itself, but we say a “wavy trail”. The “wavy trail” was part of the sense-data, but the electron wasn’t. Instead, we come to think that the electron caused the “wavy trail” that was our sense data. This means that the electron would have to be an inference from the sense-data.

Now we could come to wonder how we infer these things from the sense-data. We seem to have the option of causality. What we observe is the effect, and we come to infer the cause from the effects. We notice certain regularities in sense-data, which provide us with the laws of physics or provide the rules of inference. Like “electron caused the wavy trail.”

This can lead us to think that the physical world is the cause of the familiar world, which is the effect of the physical world. In other words, the familiar world we all experience is the effect of the physical world, which is the cause. What we experience is the effect of something else, which we call the physical world.

It shall be assumed that there is some kind of causality, either deterministic or indeterminate, which is how we make the inference from a supposed effect to cause, or from sense-datum to atoms. The obvious reason we have for believing in the law of causation is based on that observe certain regularities or sequences. When conditions A are met, it is always happens that B happens. This means that when condition A is the case, then B shows up. A is called the cause, and B is called the effect. This leads to the causal law of AB.

But these regularities are found among sense-data. A is a sense-datum, and B is a sense-datum, and any of our other cause and effect relationships ever observed by any human being have been sense-datum. This leads us to the conclusion that the cause of sense-datum is always another sense-datums, and all known causal laws apply solely to the world of sense-data. This means we have no, and could not have, one single piece of evidence for believing that the law of causation can be applied outside of the realm of sense-data, or sense-data can have any causes (like the physical objects) which aren’t sense-data themselves.

A diagram of what is going on here could help out:

A,B, and C are all sense-datum found in the familiar world. The person sees all these things, and sees that B follows A, and C follows B. This leads them to believe that A is the cause of B, and B is the cause of C. It comes to this conclusion of causality by the regular repetition of that order, and through experience. Sense-datum of billiard ball A is found to come into contact with sense-datum billiard ball B. This leads us to conclude that A is the cause of B moving.

But what right do we have, or what reason, to assert that the causes of A,B, and C are a’,b’,c’ (which are physical causes), when they’re never observed behind the sense-data? We have no right to this claim. The law of causation they operate on has never been observed to operate outside of the sense-data, and can therefore have no evidence that it does operate outside of the sense-data. It is sufficent to stick with A being the cause of B. We don’t have to invoke that a’ is the cause of A, when these aren’t part of sense-data, but A is the cause of B is part of the sense-data. We’d have to give two causes for each phenomena, one in the one world and the other in another world. One cause in the physical world and one in the familiar world.

It is not denied that a star causes light-waves, those waves cause retinal changes, the retinal changes cause changes in the optic nerve, which causes movements in the brain cells, and so on.

“But the observed causes and effects are all sense-data, or at least possible sense-data. And no sequences of sense-data can possibly justify going outside of the series of sense-data altogether. If you admit that we never observe anything except sense-data and their relations, regularities, and sequences, then it is obvious that we are completely shut in by sense-data, and can never get outside of them. Not only causal relations, but all other observed relations, upon which any kind of inferences might be founded, will lead only to further sense-data and their relations. No inference, therefore, can pass from what is sense-datum to what is not sense-datum.”

This, in the end, leads to there the fact that atoms aren’t inferences from sense-data. It is not to be denied that there is a vast amount of valid inferential reasoning taking place in a physical theory that contains atoms in it. But from a strict logical sense, there’s no inference from sense-datum to atoms. What does this mean?

“An hypothesis is set up, and the inferential processes are concerned with the application of the hypothesis, i.e. with the prediction by its aid of further sense-data, and with its own internal consistency.”

This means that atoms aren’t inferences from sense-data (i.e. experience), or can validly infer them from sense-data. This means we can’t have any reason to believe that they exist. Or, we at least, no one could know if they did, and means we have absolutely no evidence of their existence.

We might wonder the status the atoms have, or the hypothesis that contains them. It doesn’t mean that they’re false and worthless, merely untrue. We don’t come to think that the nautical almanac “exist” except on the pages of the book or in the brains of the people that compiled it or read it. But the natural almanac is “true” as much as it enables us to predict certain “sense-data”, like disks of light at night (i.e. stars). The atomic theory carries a similar function as that of the natural almanac. It helps us make predictions of experiences that we’ll have, and orderly amongst itself.

This view includes making predictions of future things, but it also includes the view to include retrodictions as well, which is making predictions about what happened in the past. For example, we could wonder where Mars was on 8,000 B.C.E. We use our hypothesis, say Newton’s. With this hypothesis, the theory makes a retrodiction of where Mars was around 8,000 B.C.E.

Stace suggests that hypothesis, like the theory of the atoms, are shorthand formula ingeniously worked out by the human mind. And they enable us to predict experiences. He gives us the example of Newton’s “force”.

“Newton formulated a law of gravitation in terms of “forces.” It was supposed that this law-which was nothing but a mathematical formula-governed the operation of these existent forces. Nowadays it is no longer believed that these forces exist at all. And yet the law can be applied just as well without them to the prediction of astronomical phenomena. It is a matter of no importance to the scientific man whether the forces exist or not…But that would not make the law useless or untrue (if Newton’s “force” didn’t exist). If it could still be used to predict phenomena, it would be just as true as it was.”

Instead, we’ve found that Newton’s “forces” couldn’t account for the orbit of Mercury, and a new theory was developed. It was developed based on Einstein’s theory. Einstein’s theory talks about bumps and space bending and creating hills in the space-time fabric. And this helped get ride of Newton’s “forces” in science. But this doesn’t put Einstein’s theory off any better.

“Not only may it be said that forces do not exist. It may with equal truth be said that “gravitation” does not exist. Gravitation is not a “thing,” but a mathematical formula, which exists only in the heads of mathematicians. And as a mathematical formula cannot cause a body to fall, so gravitation cannot cause a body to fall. Ordinary language misleads us here. We speak of the law “of” gravitation, and suppose that this law “applies to” the heavenly bodies. We are thereby misled into supposing that there are two things, namely, the gravitation and the heavenly bodies, and that one of these things, the gravitation, causes changes in the other. In reality nothing exists except the moving bodies, or moving sense-data. And neither Newton’s law nor Einstein’s law is, strictly speaking, a law of gravitation. They are both laws of moving sensedata, that is to say, formulae which tell us how the sense-data will move.”

We tend to think that these things exist, and that is because the human mind hasn’t broken free of the idea that science “explains” things. People weren’t just content with laws that told them planets, as a matter of fact, move in such and such ways. People wanted to know “why” planets moves these ways. Newton replied because of “Forces”. And humanity thought that explained why the planets move in such and such way. That’s because we understand forces, we feel them every time someone pushes or pulls us. This is suppose to have explained by things that are familiar to us in our own experiences. And the same happened with Einstein’s “humps and hills” of space-time.

“But scientific laws, properly formulated, never “explain” anything. They simply state, in an abbreviated and generalized form, what happens. No scientist, and in my opinion no philosopher, knows why anything happens, or can “explain” anything. Scientific laws do nothing except state the brute fact that “when A happens, B always happens too.” And laws of this kind obviously enable us to predict.”

Atoms are said to be in the same position as “Forces” of Newton’s and “Humps and Hills” of Einstein. And so too with the theory of atoms are exactly like them. They’re, in reality, mathematical formulae, and this is the scientific way of stating the atomic theory. This formulae helps to eventually lead to predictions, and these predictions are of sense-data that will appear in given conditions. It will, for example, enable a scientist to predict a “wavy trail”. And the human minds weakness for seeking explanation leads us to think that atoms exist in correspondence with the mathematical formula.

In seeking explanations, we try to come up with causes for events of our experience. And we’ve come to think of causation as a principle of explanation. But we don’t experience atoms as the cause of our sense-data, and so we can’t really say that atoms explain anything. The relation of atoms to sense-data isn’t a relation of cause to effect, but relation of mathematical formula to facts and happenings that enables the mathematician to calculate.

We come to think of these things existing because they give us a “physical” cause for the effects in the “familiar” world. And some scientists cling to the existence of atoms because they cling to explanation. But so did those during Newton’s time that “Forces” existed because they explained things. But it is the imagination that has explained things. It explains things by making them more familiar to us, and more homely. Maybe an example could help with this.

“One of the foundations of physics is, or used to be, the law of the conservation of energy. I do not know how far, if at all, this has been affected by the theory that matter sometimes turns into energy. But that does not affect the lesson it has for us. The law states, or used to state, that the amount of energy in the universe is always constant, that energy is never either created or destroyed. This was highly convenient, but it seemed to have obvious exceptions. If you throw a stone up into the air, you are told that it exerts in its fall the same amount of energy which it took to throw it up. But suppose it does not fall. Suppose it lodges on the roof of your house and stays there. What has happened to the energy which you can nowhere perceive as being exerted? It seems to have disappeared out of the universe. No, says the scientist, it still exists as potential energy. Now what does this blessed word “potential”-which is thus brought in to save the situation-mean as applied to energy? It means, of course, that the energy does not exist in any of its regular “forms,” heat, light, electricity, etc. But this is merely negative. What positive meaning has the term? Strictly speaking, none whatever. Either the energy exists or it does not exist. There is no realm of the “potential” half-way between existence and non-existence. And the existence of energy can only consist in its being exerted. If the energy is not being exerted, then it is not energy and does not exist. Energy can no more exist without energizing than heat can exist without being hot. The “potential” existence of the energy is, then, a fiction. The actual empirically verifiable facts are that if a certain quantity of energy e exists in the universe and then disappears out of the universe (as happens when the stone lodges on the roof), the same amount of energy e will always reappear, begin to exist again, in certain known conditions. That is the fact which the law of the conservation of energy actually expresses. And the fiction of potential energy is introduced simply because it is convenient and makes the equations easier to work. They could be worked quite well without it, but would be slightly more complicated. In either case the function of the law is the same. Its object is to apprise us that if in certain conditions we have certain sense-data (throwing up the stone), then in certain other conditions we shall get certain other sense-data (heat, light, stone hitting skull, or other such). But there will always be a temptation to hypostatize the potential energy as an “existence,” and to believe that it is a “cause” which “explains” the phenomena.”

If the views which I have been expressing are followed out, they will lead to the conclusion that, strictly speaking, nothing exists except sense-data (and the minds which perceive them). The hypothesis truth and value consist in their capacity for helping us to organize our experience and predict our sense-data. But we eventually have to come to the conclusion that the “real” world is the “physical world”. It is the “physical world” that is the illusion, and the familiar world that is the reality. It’s the only world that exists, or ever known to exist.